Bradded earth cable CSA

[Kyran]

Hi People

What the CSA classed as of the cables that are bradded and not the now normal PVC sheathed cables.

Thanks

 

[Darkwood]

Assume you mean Braided?
Not sure what you are asking here its hard to translate your question?

The cable sizing i.e. 1mm, 1.5mm etc follow the same standard sizing as normal flex.

If you are asking what the CSA of the braiding is to act as an earth conductor in a SY style cable then you cannot use it as an earth its purpose is as a screen but must be earthed if using the cable with Low Voltages.

 

[Kyran]

Ops typo, sorry. yes I meant braided. I looked me question again, not very well written i admit. What i mean is i seen on a potential clients supply cable a flat braided looking ribbon that comes of the sheath of the supply cable to an MET, the wire braid has no sheath covering it and is flat hence the question what its CSA, as With PVC sheath main earth cables are round and would be 25mm 16mm ect.


No i was not talking about the SY style cables.

 

[Simonslimline]

Sounds like a DNO TN-s possibly!

Is this the main supply to the property?

 

[Kyran]

Sounds like a DNO TN-s possibly!

Is this the main supply to the property?

YES. just looks a bit odd thats all.

 

[telectrix]

measure the width and thickness... w x t = csa.... or use the csa of your earthing conductor to the MET

 

[Simonslimline]

Whats the Ze?

I worked on a house once where the supply was TN-s and the DNO had just used insulation tape to attach some earth braid to the sheath then terminated in to the MET.


If your concerned then ring them. Probably be a waste of time though.

 

[Kyran]

Thanks simple answer in the end. : )

 

[D Skelton]

If you are asking what the CSA of the braiding is to act as an earth conductor in a SY style cable then you cannot use it as an earth its purpose is as a screen but must be earthed if using the cable with Low Voltages.

Totally agree with the sentiment, I for one would never not earth an SY braid,then again I wouldn't be using it for mains voltage. When you say it must be earthed, this isn't entirely accurate. I would have maybe said, you'd be an idiot not to earth it, but it cannot actually be used as an earth. I'd have also posed the question as to why SY was being used for anything other than ELV.

That said, it's kind of irrelevant to the thread now

 

[topquark]

I get the impression folks don't like earthing the braiding coz they think it can't handle the current under fault conditions. I posted the other day about this ... 2.5mm equiv csa in braiding will take 30A, 4.0mm will handle 40A, if there's ever a concern with earthing the braiding ask the manuf for specs. Not recommending using the braiding as the only earth though, always use a core in addition.

 

[Knobhead]

If you need the CSA of the braid from a DNO PILC cable, look up Hepworth clamps. If it’s sweated to the sheath then you need to measure it as Tel said, it could be anything. The measurement you get will be oversized by about 10% and the it will be an imperial size.

 

[Lucien Nunes]

When measuring, make sure the strands are tightly packed into shape otherwise the measurement will be oversize by much more than the 10% Tony mentions. The fill factor can be as low as 40%, i.e the CSA of a particular size compared to solid copper of the same size. It might be better to compare with manufacturers sizes as Tony also recommends.

See Braid Sizes for example.

It's very easy to make large errors in CSA from size measurements because they get squared.
E.g. if a 16mm² conductor were 8 x 2mm, and you measured it as 9 x 3mm, the calculated CSA would be 27mm² or 69% too high.

 

[Knobhead]

It’s one of those weird things, the lower the fill factor the better its CCC / CSA.

I’ve never had to sweat a fly lead on to PILC as we used either brass cones or lead lined glands so you had a bolted connection.